Seems I've managed to do the same myself after some back and forth to Samsung, with some success. BEFORE I've installed any apps, I now have 18% (152MB) Free.

It's a really important step when applying the update that you actually reset the TV from the on/off button on the TV itself.

My issue was that it's not actually immediately apparent that there is a button on some of the later models so this is why I had follow on issues. It's actually hidden under the Samsung logo, to the rear of the TV.

If you follow the instructions I posted earlier, it actually works. I must have tried about 6 or 7 times before I got the sequence right, but you need to make sure you hold the button for 5 seconds, then press and hold the button on the TV remote.

Storage available immediately after the reset (pre any of the forced applications downloading):

It was the steps outlined before by another poster, hold down power button on tv for 5 seconds and then immediately press the power button on the smart remote, hey presto for me, and i still may try the e-manual delete which should free up another 199mb 👍

Ive installed the latest 1292 update and it gave me 9% free after a hard reboot and smarthub reset. however, an hour mins later, I re-checked the free space and it dropped down to 3%. ...so as far as I'm concerned, I'm no better off! At best I can only install 2 x 10Mb apps! I'll be going back to samsung about this.